Vibrating debris remover

ABSTRACT

This invention relates to a device which is either permanently attached or removable to the edge of a material such as a vehicular glass window. This device may be comprised of a converter sub-unit (vibrator) and an amplifying coupler. These elements are arranged so as to propagate mechanical motion generated by the converter sub-unit through the amplifying coupler and into the edge of the attached material. The resulting vibration motion in the material, which could take the form of a longitudinal compression/rarefaction wave, transverse wave, or a combination of the two waveforms, is of a sufficient magnitude so as to cause the adhesive bond between the material&#39;s surface and other solid debris, such as ice, to be quickly broken. This allows the debris to fall away while not damaging the material. The vibration motion in the material is also of sufficient magnitude to remove a liquid such as water from the material surface.

This application claims the benefit of U.S. Provisional Application Ser.No. 60/550,567, filed Mar. 4, 2004, which is hereby incorporated hereinby reference.

TECHNICAL FIELD

This invention relates to a device that when attached along the edge ofa material, such as a vehicular window, will propagate mechanicalvibration or shock motion created by the device into the material withsufficient magnitude in order to remove solid debris, such as ice,and/or liquid debris, such as water, from the surface of the material.The present invention shall be described chiefly with respect to anapplication for the removal of ice and/or water from the windshield ofan automobile. However, it will be easily understood that the describedapplication of the invented device is in no way restrictive to a greatmany other applications in which the removal of debris from other typesof material surfaces may be required. Some examples of otherapplications include ice removal from aircraft wings, adhesive removalon/or between two materials, cookware cleaning, and the removal of paintfrom a material surface.

GOVERNMENT INTEREST

This invention was made by an employee of the Untied States Government.The Government has a nonexclusive, irrevocable, royalty-free license inthe invention with power to grant licenses for all governmentalpurposes.

BACKGROUND OF THE INVENTION

It is important for the safe operation of any vehicle that a clear,unobstructed view to the outside environment be maintained. An exampleof such viewing need is for the driver of an automobile. In thisapplication, material such as the windshield, side windows, rearviewmirrors, and rear windows have a surface exposed to the outside weatherelements where rain, snow, ice, and other debris can accumulate. Theaccumulation of this debris poses a significant problem with maintaininga clear view to the outside environment.

In an attempt to maintain a clear view to the outside environment, adevice utilizing mechanical motion has been developed. This device,which is either removable or permanently attached to the edge of amaterial, is comprised of two elements, a converter sub-unit and anamplifying coupler sub-unit. The converter sub-unit converts an energysource such as electrical, pneumatic, or fluid into mechanical vibrationor shock pulse motion. The amplifying coupler sub-unit transfers themechanical motion generated by the converter sub-unit into the attachedmaterial. Also, the amplifying coupler sub-unit can be designed toreduce, magnify, or keep constant the amplitude of the convertersub-unit mechanical motion before it enters the material.

In prior art, one method used to remove solid debris such as ice from amaterial surface consists of a device which blows hot air on thematerial's interior surface or heats the material surface by the Jouleeffect through metal wires attached to the material. A major drawback tothese devices is that the time it takes to remove the debris issignificant. Also, the field of view is obstructed with the metal wiretechnology.

In other prior art, another method used to remove debris such as iceand/or liquid from a material surface consists of mounting transducerelements, which vibrate, directly onto the material surface. Thetransducer elements are made from piezoelectric or magnetostrictivematerial and electrical energy is used to make these elements vibrate. Amajor drawback of these devices is that the vibrating transducerelements mount perpendicular and directly on the material surface.Because the vibrating transducer elements are attached in this manner,the magnitude of the vibrations developed by the transducer elementscannot be altered, and in particular magnified, prior to entering intothe material. This results in a design which is very inefficient becauseof the amount of energy required to generate the necessary vibrationamplitude in the material to remove the unwanted debris. Anotherdrawback of these devices is that the dimensions of the vibratingtransducer piezoelectric or magnetostrictive elements have to becarefully chosen such that their natural vibration frequency is tuned tothat of the material in order that the device works efficiently.Additionally, some of the above referenced devices are mounted on thematerial surface in such a way that the field of view through thematerial can be highly obstructed if applied in the use of windshield orside windows for removing debris.

SUMMARY OF THE INVENTION

Accordingly, the intent of this present invention is to overcome thedrawbacks of prior art methods used for the removal of debris from amaterial surface. To achieve this intent and in accordance with theprinciples of the invention as embodied and broadly described herein,the invented device is comprised of two elements, a converter sub-unitand an amplifying coupler sub-unit. These two elements are used togetherto efficiently propagate mechanical motion or vibrations into the edgeof a material causing the material to vibrate. Because the material isvibrating with sufficient displacement and acceleration, the removal ofthe debris is achieved by breaking the adhesive bond existing betweenthe material and the undesired debris. This is done without harming thematerial and without obstructing the view through the material.

Therefore, the present invention provides a system for removing ice,water, or other debris from a material, by causing vibrational motion tooccur in the material. The vibrations in the material are the result ofmechanical vibration or a shock pulse motion entering into the edge ofthe material through the use of an amplifying coupler sub-unit. Thisfeature is unlike prior art methods in which devices are attachedperpendicular to the material surface and do not incorporate anamplifying coupler sub-unit in their designs.

This invention also provides a debris removal system in which thevibration frequency is adjustable, if required, for matching theresonating vibration frequency of the material with debris attached.

SUMMARY OF THE DRAWINGS

FIG. 1 is a side view of a Vibrating Debris Remover attached to amaterial with debris, in accordance with a preferred embodiment of thepresent invention.

FIG. 2 is a schematic view showing various types of mechanical vibrationwaveforms present in material.

FIG. 3 is a side view of a preferred embodiment of a Vibrating DebrisRemover converter sub-unit.

FIG. 4 is a graphic representation illustrating sinusoidal vibrationmotion at the converter sub-unit tip.

FIG. 5 is a graphic representation illustrating random vibration motionat the converter sub-unit tip.

FIG. 6 is a graphic representation illustrating complex vibration motionat the converter sub-unit tip.

FIG. 7 is a graphic representation illustrating shock pulse vibrationmotion at the converter sub-unit tip.

FIG. 8 is a schematic view illustrating a Vibrating Debris Removerpiezoelectric converter sub-unit.

FIG. 9 is a side view of an amplifying coupler sub-unit with steppedgeometry, in accordance with a preferred embodiment of the presentinvention.

FIG. 10 is a side exploded view of a converter sub-unit connected to anamplifying coupler sub-unit via a threaded stud fastener.

FIG. 11 is a partial cross-sectional view of a converter sub-unitconnected to an amplifying coupler sub-unit via a support frame.

FIG. 12 is a side view illustrating a converter sub-unit and amplifyingcoupler sub-unit made from same material, in accordance with a preferredembodiment of the present invention.

FIG. 13 is a schematic representation illustrating stress transmissiondefinition across an interface.

FIG. 14 is a side schematic view illustrating amplifying couplersub-unit-to-material connection definitions.

FIG. 15 is a schematic view illustrating an amplifying coupler sub-unitwith stepped geometry stress transmission definition.

FIG. 16 is a side view of an amplifying coupler sub-unit with no steppedgeometry, in accordance with a preferred embodiment of the presentinvention.

FIG. 17 is a side schematic view of an amplifying coupler sub-unit withstepped geometry; area A₁>area A₂, in accordance with a preferredembodiment of the present invention.

FIG. 18 is a side schematic view of an amplifying coupler sub-unit withstepped geometry; area A₁<area A₂, in accordance with a preferredembodiment of the present invention.

FIG. 19 is a graphical representation illustrating examples ofamplifying coupler sub-unit geometries.

FIG. 20 is a schematic view of a material on which debris is attached.

FIG. 21 is a side, partially cross-sectional, view of an amplifyingcoupler sub-unit connected to material via a fastener, in accordancewith a preferred embodiment of the present invention.

FIG. 22 is a side, partially cross-sectional, view of an amplifyingcoupler sub-unit connected to material via a support frame, inaccordance with a preferred embodiment of the present invention.

FIG. 23 is a side view of an amplifying coupler sub-unit connected tomaterial via an adhesive bond, in accordance with a preferred embodimentof the present invention.

FIG. 24 is a side view of an amplifying coupler sub-unit with an offsetconnection to material via an adhesive bond, in accordance with apreferred embodiment of the present invention.

FIG. 25 is a side view of an amplifying coupler sub-unit and materialformed integrally.

FIG. 26 is a top schematic view of an amplifying coupler sub-unitredirecting mechanical motion from a converter sub-unit.

FIG. 27 is a perspective view illustrating three vibrating debrisremovers applied to an automobile windshield, in accordance with apreferred embodiment of the present invention.

FIG. 28 is a perspective, partially cut-away view of a vibrating debrisremover applied to an aircraft wing, in accordance with a preferredembodiment of the present invention.

DETAILED DESCRIPTION

The concern for the removal of debris from a material is very real. Thepresent invention shall be described with respect to an automotivewindshield. However, this should in no way be restrictive, as a greatmany other materials and applications exist to which this inventeddebris removal device could be employed.

As shown in FIG. 1, some type of debris 5, such as ice and or water, canbuild on a material 3 surface, such as an automobile windshield, to alevel where visibility to the outside environment is impaired. Thisresults in a dangerous operating condition. A vibrating debris remover 6has been invented that can remove debris 5, such as ice, from a material3 surface, such as an automotive windshield 40 or aircraft airframe 43.The vibrating debris remover 6 consists of two parts, the convertersub-unit 1 and the amplifying coupler sub-unit 2 to which the material 3is attached.

The converter sub-unit 1 and amplifying coupler sub-unit 2 are soarranged as to propagate mechanical vibration or shock pulse motiongenerated by the converter sub-unit 1 into the amplifying couplersub-unit 2 and then into the edge of the material 3. The amplifyingcoupler sub-unit 2 can be designed to reduce, magnify, or keep constantthe amplitude of the converter sub-unit's 1 mechanical vibration orshock pulse motion before it enters the material 3 to which is attachedsome debris 5 particle.

The resulting vibrations 13 in the material 3 will be in the form of alongitudinal 7 motion, transverse 8 motion, or a combination 9 of thetwo based on how the amplifying coupler sub-unit 2 is attached to thematerial 3. The longitudinal 7 motion in the material 3 is the result ofcompressions 10 and rarefactions 11 in the material's molecular density12 and is only in the direction of the propagating vibrations. Thelongitudinal 7 motion requires a change in the volume or moleculardensity 12 of the material 3. The transverse 8 motion is perpendicularto the direction of the propagating vibrations and is a result of shearstresses in the material 3. The longitudinal 7 motion, transverse 8motion, or a combination 9 of the two in the material 3 is of asufficient magnitude and strain rate such that the adhesive bond betweenthe material 3 and debris 5 is quickly broken allowing the debris 5 tofall away while not damaging the material 3. The vibrations 13 (showingthe shift in molecular density as a function of position, x, or time, t,for a single wavelength λ) in the material 3 are also of sufficientmagnitude as to cause water droplets 5 to leave the material 3 surface.

1.0 Converter Sub-Unit

As shown in FIG. 1 and FIG. 3, the converter sub-unit 1 has the purposeof converting an external energy source 4 such as electrical, pneumatic,or fluid into longitudinal mechanical motion 14 at the convertersub-unit tip surface 15. For example, the longitudinal mechanical motion14 of the converter sub-unit tip surface 15 could take the form of asine wave (FIG. 4), random wave (FIG. 5), complex wave (FIG. 6), or apulse wave (FIG. 7). In addition, the longitudinal mechanical motion 14of the converter sub-unit tip surface 15 could be a combination of allor some of the above mentioned waveforms.

There are several devices in existence which can perform the function ofthe converter sub-unit 1. As an example, an electrical energy source 4can be converted into longitudinal mechanical vibration motion 14 of theconverter sub-unit's acoustic transformer surface 15 through the use ofa piezoelectric transducer consisting of piezoelectric material 16 asshown in FIG. 8. An electrical oscillator energy source 4 is passed tothe piezoelectric material via electrodes causing the piezoelectricmaterial 16 to expand and contract (i.e. vibrate). As the piezoelectricmaterial 16 expands and contracts, it pushes against an acoustictransformer, causing the acoustic transformer surface 15 to vibrate.Electrical energy 4 can also be converted into longitudinal mechanicalvibration motion 14 of the converter sub-unit tip surface 15 through theuse of a magnetostrictive transducer.

An electrical energy source 4 can also be converted into longitudinalmechanical vibration motion 14 of the converter sub-unit tip surface 15through the use of an electric motor and gearing.

As a further example, a pneumatic energy source 4 can be converted intolongitudinal mechanical vibration motion 14 of the converter sub-unittip surface 15 through the use of a pneumatic hammer.

As a final example, longitudinal mechanical vibration motion 14 of theconverter sub-unit tip surface 15 can be created through the use ofwhistles and sirens which use a fluid jet energy source 4, such ascompressed air, to pass through an orifice, causing the convertersub-unit tip surface 15 to vibrate.

As an example of a device that can create a longitudinal mechanicalshock pulse motion, an electrically activated solenoid can be used tocause the movement of a plunger component. This plunger component can bea metal rod such that when it contacts another surface, a shock pulse iscreated which travels into the contacting surface 17 such as the one onthe amplifying coupler sub-unit 2.

2.0 Converter Sub-Unit to Amplifying Coupler Sub-Unit Attachment

The converter sub-unit tip surface 15 is in contact with the amplifyingcoupler sub-unit surface 17, an example of which is shown in FIG. 9.These two surfaces are connected to each other in such a fashion toensure that the longitudinal mechanical vibration and/or shock pulsemotion 14 from the converter sub-unit tip surface 15 transfers into theamplifying coupler sub-unit surface 17. This causes the amplifyingcoupler sub-unit surface 17 to have longitudinal vibration motion 18which transfers through the amplifying coupler sub-unit 2 and createslongitudinal mechanical vibration and/or shock pulse motion 19 at theamplifying coupler sub-unit tip surface 20.

For example, as shown in FIG. 10, the connection could be made with aninserted threaded stud 21. Attachment of the converter sub-unit 1 andthe amplifying coupler sub-unit 2 onto the threaded stud 21 is made suchthat the converter sub-unit tip surface 15 and the amplifying couplersub-unit surface 17 are placed and remain in compression. Thisconfiguration results in a design which the converter sub-unit 1 can beremoved and replaced relatively easily.

As an additional example, as shown in FIG. 1, the converter sub-unit tipsurface 15 and the amplifying coupler sub-unit surface 17 could beplaced in compression by pushing the converter sub-unit tip surface 15up against the amplifying coupler sub-unit surface 17 through the use ofa clamping device 22 such that the converter sub-unit tip surface 15 andthe amplifying coupler sub-unit surface 17 are placed and remain incompression. This configuration also results in a design which theconverter sub-unit 1 can be removed and replaced.

As shown in FIG. 12, the converter sub-unit tip surface 15 andamplifying coupler sub-unit surface 17 could be made nonexistent becausethe converter sub-unit 1 and the amplifying coupler sub-unit 2 are madefrom a single piece of material 23. In this arrangement, the convertersub-unit 1 would not be removable from the amplifying coupler sub-unit2. This configuration results in a design that would create a moredifficult maintenance situation if the converter sub-unit 1 had to bereplaced.

3.0 Converter Sub-Unit to Amplifying Coupler Sub-Unit Material Matching

In addition to an interface that can transfer motion between theconverter sub-unit tip surface 15 and the amplifying coupler sub-unitsurface 17, it is also advantageous to understand what impedance valuesexist between the materials used for the converter sub-unit 1 and theamplifying coupler sub-unit 2. By understanding the material impedances,the values of the stress wave reflection and stress wave transmissioncoefficients can be calculated at the interface of the convertersub-unit tip surface 15 to the amplifying coupler sub-unit surface 17.The longitudinal mechanical vibration and/or shock pulse motion 14 ofthe converter sub-unit tip surface 15 is transferred by a force from theconverter sub-unit tip surface 15 pushing up against the amplifyingcoupler sub-unit surface 17. Since this force is acting through thecross sectional area of the converter sub-unit tip surface 15, a stressstate is present at this interface.

This stress state is important to know because there are cases in whichthe longitudinal mechanical vibration and/or shock pulse motion 14 ofthe converter sub-unit tip 15 does not create any substantiallongitudinal mechanical vibration and/or shock pulse motion 18 at theamplifying coupler sub-unit surface 17. This condition exists if thereis a significant difference between the impedance values of theconverter sub-unit 1 and amplifying coupler sub-unit 2 materials. Theresult is a very inefficient design and the amount of energy 4 requiredfor the converter sub-unit 1 to remove debris 5 on the material surface3 would be unreasonably high.

Referring to FIG. 13 and assuming that the converter sub-unit tipsurface 15 and the amplifying coupler sub-unit surface 17 have identicalcross sectional areas, mathematical equations (1) and (2) can be used todetermine the stress transmission and stress reflection coefficients atthis interface.

$\begin{matrix}{r = \frac{Z_{2} - Z_{1}}{Z_{2} + Z_{1}}} & {{Equation}\mspace{20mu}(1)} \\{t = \frac{2Z_{2}}{Z_{2} + Z_{1}}} & {{Equation}\mspace{20mu}(2)}\end{matrix}$Where:

r=the stress reflection coefficient

t=the stress transmission coefficient

Z₁=impedance of material 1

Z₂=impedance of material 2

Using equations (1) and (2), it can be shown that if the materialproperties of the converter sub-unit and amplifying coupler sub-unit arethe same, then Z₁=Z₂, the stress reflection coefficient is zero, and thestress transmission coefficient is one. This means that the incidentstress wave 24 is completely transmitted with no reflected stress wave26. The incident stress wave 24 and the transmitted stress wave 25 havethe same magnitudes.

However, if Z₁>Z₂, it can be shown using equations (1) and (2) that themagnitude of the transmitted stress wave 25 will have less magnitudethan the original incident stress wave 24. In addition, the reflectedstress wave 26 will have a negative value. This means that an incidentstress wave 24 that is compressive 10 in nature will be reflected 26 asa rarefaction 11 and that an incident stress wave 24 that is ararefaction 11 in nature will be reflected 26 as a compressive 10 wave.

Also notice that if Z₁<Z₂, it can be shown using equations (1) and (2)that the stress reflection coefficient is greater than a value of zeroand the stress transmission coefficient is greater than a value of one.This means that the incident stress wave 24 is amplified through thejoint and that the transmitted stress wave 25 has a higher magnitudethan the incident stress wave 24.

By choosing the proper materials for the converter sub-unit 1 andamplifying coupler 2, an efficient transfer of stress 25 can be achievedat the converter sub-unit tip surface 15 to amplifying coupler surface17.

4.0 Amplifying Coupler Sub-Unit

The amplifying coupler sub-unit 2 has the purpose of transmitting theconverter sub-unit's 1 longitudinal mechanical vibration and/or shockpulse motion 14 into the edge 27 of the material 3. There are severaladvantages to using an amplifying coupler sub-unit 2. These advantagesare: (I) the converter sub-unit 1 can be easily removed for repairs andalso easily installed, (II) the amplifying coupler sub-unit 2 can serveas an impedance buffer to better match that of the converter sub-unittip 15 material to that of the material 3 with attached debris, (III)the amplifying coupler sub-unit 2 can be designed to reduce, magnify, orkeep constant the amplitude of the converter sub-unit's 1 mechanicalmotion 14 before it enters the material 3, (IV) it can direct thelongitudinal mechanical vibration and/or shock pulse motion developed bythe converter sub-unit 1 in a direction which is not the same as thelongitudinal mechanical vibration and/or shock pulse motion direction inthe material 3, and (V) the amplifying coupler sub-unit 2 can bespecially designed to attach to the material 3 edge 27 as shown in FIG.14.

As an example to explain how the amplifying coupler sub-unit 2 can bedesigned to serve as an impedance buffer, or how it can be designed toreduce, magnify, or keep constant the amplitude of the convertersub-unit's 1 mechanical motion 14 before it enters the material 3,mathematical equations (3) and (4) can be used.

Referring to FIG. 15 and equations (3) and (4) the knowledge of howstress will transfer through an interface 28 of two different materialsand a step in cross sectional areas is presented. FIG. 15 represents aside view of an amplifying coupler sub-unit 2 that utilizes a stepchange in height along its length.

These equations take into account driving point impedances, differencesof material properties, and cross sectional areas to determine therelationship between the incident, reflected, and transmitted stresswaves.

These equations are:

$\begin{matrix}{\sigma_{t} = {\frac{2( \frac{Z_{2}^{*}}{Z_{1}^{*}} )( \frac{A_{1}}{A_{2}} )}{1 + ( \frac{Z_{2}^{*}}{Z_{1}^{*}} )}\sigma_{i}}} & {{Equation}\mspace{14mu}(3)} \\{\sigma_{r} = {\frac{( \frac{Z_{2}^{*}}{Z_{1}^{*}} ) - 1}{1 + ( \frac{Z_{2}^{*}}{Z_{1}^{*}} )}\sigma_{i}}} & {{Equation}\mspace{14mu}(4)}\end{matrix}$Where:

σ_(i)=the incident stress 31 (traveling in material 1 toward material 2)

σ_(r)=the stress reflection 29 back into material 1

σ_(t)=the stress transmitted 30 into material 2

Z*₁=driving point impedance of material 1

Z*₂=driving point impedance of material 2

A₁=cross sectional area of material 1

A₂=cross sectional area of material 2

And since force balance at the interface 28 must be maintained, thefollowing force balance relationship must be achieved:A ₁(σ_(i))=A ₂(σ_(t))−A ₁(σ_(r))  Equation (5)

4.1 Example of an Amplifying Coupler Sub-Unit of a Single Material andNo Step Change in Area

Since in this case the amplifying coupler sub-unit 2 is made of a singlematerial, Z*₁=Z*₂. Referring to FIGS. 15 and 16 and using equations (3)and (4), it is shown that as long as there is no cross sectional areachanges in the amplifying coupler sub-unit 2, there will be no reflectedstress wave 29. Also, the transmitted stress wave magnitude 30 is equalto the incident stress wave 31. Thus the longitudinal mechanicalvibration and/or shock pulse motion 18 at the amplifying couplersub-unit surface 17 and the longitudinal mechanical vibration and/orshock pulse motion 19 present at the amplifying coupler sub-unit tipsurface 20 will have the same magnitude. Using equation (5), forcebalance across the interface 28 is maintained.

In reality there will be some damping losses in the amplifying couplersub-unit 2 which will cause the longitudinal mechanical vibration and/orshock pulse motion 19 at the amplifying coupler sub-unit tip 20 to belower in magnitude than the longitudinal mechanical vibration and/orshock pulse motion 18 at the amplifying coupler sub-unit surface 17.However, the material damping loss factors can be minimized.

4.2 Example of an Amplifying Coupler Sub-Unit of a Single Material witha Step Change in Area

Referring to FIGS. 15 and 17 and using equations (3) and (4), it isshown that if the amplifying coupler sub-unit 2 has a cross sectionalarea change in which cross sectional area A₁ (which is a function of thediameter or thickness dimension h₁) is larger than cross sectional areaA₂ (which is a function of the diameter or thickness dimension h₂), theamplifying coupler sub-unit will have a reflected stress wave 29 thathas a magnitude that is less than the incident stress wave 31 and willhave the opposite sign of the incident wave. This opposite sign meansthat an incident compressive stress wave is reflected as a rarefaction(tension) stress wave and an incident rarefaction stress wave isreflected as compression stress wave. The transmitted stress wave 30will be greater in magnitude than the incident stress wave 31. As acheck, the force balance of equation (5) is maintained.

Referring to FIGS. 15 and 18 and using equations (3) and (4), it isshown that if the amplifying coupler sub-unit 2 has a cross sectionalarea change in which cross sectional area A₁ (which is a function of thediameter or thickness dimension h₁) is smaller than cross sectional areaA₂ (which is a function of the diameter or thickness dimension h₂), theamplifying coupler sub-unit will have a reflected stress wave 29 thathas a magnitude which is less than the incident stress wave 31 and willhave the same sign of the incident wave. This same sign means that anincident compressive stress wave is reflected as a compressive stresswave and an incident rarefaction (tension) stress wave is reflected asrarefaction stress wave. The transmitted stress wave 30 will be smallerin magnitude than the incident stress wave 31. As a check, the forcebalance of equation (5) is maintained.

As can be seen from equations (3) and (4), there are a great manycombinations of material driving point impedances and area ratios thatcould be used in designing the stepped amplifying coupler sub-unit 2.However, it can be stated that if the stepped amplifying couplersub-unit 2 is made of a single material and there is a step change inheight along the amplifying coupler sub-unit such that A₁>A₂ and sincestress is proportional to displacement, then the magnitude of thelongitudinal mechanical vibration and/or shock pulse motion 19 of theamplifying coupler sub-unit tip surface 20 will be greater than thelongitudinal mechanical vibration and/or shock pulse motion 18 of theamplifying coupler sub-unit surface 17 based only on these parameters.

4.3 Other types of Amplifying Coupler Sub-Unit Geometries

There are other amplifying coupler sub-unit 2 designs that do notutilize a step change in area along the amplifying coupler sub-unit 2length to amplify the longitudinal mechanical vibration and/or shockpulse motion 18 of the amplifying coupler sub-unit surface 17. Thesedesigns still have a change in height between the amplifying couplersub-unit surface 17 and the amplifying coupler sub-unit tip surface 20but utilize other geometries to achieve this. As examples of these othergeometries, FIG. 19 shows the side views of amplifying coupler sub-units2 that have the following geometries: step 32, catenoidal 33,exponential 34, and linear taper 35. FIG. 19 also shows how the maximumdisplacements X_(max)(t) and internal material stresses σ_(max)(t) varyalong the length of the amplifying coupler sub-unit 2.

There are many choices for the amplifying coupler sub-unit geometries.Several engineering text books are available that go into great detailas to how to calculate engineering parameters such as displacement andinternal material stress of amplifying coupler sub-units 2 that havevarious geometric properties.

5.0 Amplifying Coupler Sub-Unit to Material Surface Attachment

The amplifying coupler sub-unit tip surface 20 is in contact with theedge 27 of the material 3. These two surfaces are connected to eachother in such a fashion as to ensure that the longitudinal mechanicalvibration and/or shock pulse motion 19 from the amplifying couplersub-unit tip surface 20 transfers into the material 3 of interestcausing the material to vibrate 36 with a longitudinal 7, transverse 8,or both a longitudinal and transverse motion 9.

The amplifying coupler sub-unit 2 can be connected to the material 3 atsome angle, Φ, as shown in FIG. 14. If the amplifying coupler sub-unitis attached parallel, Φ=0°, to the material surface, then a longitudinalwave 7 will be present in the material 3. If the amplifying couplersub-unit 2 is connected to the material 3 such that 0°<Φ<90°, then alongitudinal and transverse wave 9 will be present in the material 3. Ifthe amplifying coupler sub-unit is attached perpendicular, Φ=90°, to thesurface, then a transverse wave 8 will be present in the material 3. Inany attachment configuration, consideration must be given to ensure thatthe vibration 36 resulting in the material is sufficient to break theadhesive bond between the debris 5 and the material 3 surface.

For example, as shown in FIG. 21, the connection could be made with aninserted fastener 37 attaching the amplifying coupler sub-unit 2 and thematerial 3 together such that the amplifying coupler sub-unit tipsurface 20 and the material edge 27 are preferably placed and remain incompression.

Additionally, as shown in FIG. 22, the amplifying coupler sub-unit tipsurface 20 and the material edge 27 could be placed and remain incompression by pushing the amplifying coupler sub-unit tip surface 20 upagainst the material edge 27 through the use of a clamping device 38such that the amplifying coupler sub-unit tip surface 20 and thematerial edge 27 are placed and remain in compression.

As shown in FIG. 23, the amplifying coupler sub-unit tip surface 20 andmaterial edge 27 could be glued together with an adhesive 39. During theadhesive application process, the amplifying coupler sub-unit tipsurface 20 and the material edge 27 would be preferably placed incompression with each other and held in place until the adhesive 39cures. After the adhesive 39 cures, the two surfaces would be held inplace by the adhesive 39 with longitudinal mechanical vibration and/orshock pulse motion transferring from the amplifying coupler sub-unit 2into the material 3 through the adhesive. This similar process could beused to attach the converter sub-unit surface 15 to the amplifyingcoupler sub-unit surface 17.

As shown in FIG. 24, the amplifying coupler sub-unit 2 and material 3could be glued together with an adhesive 39 along the side surfaces.During the adhesive process, the amplifying coupler sub-unit 2 and thematerial 3 would be placed in compression with each other and held inplace until the adhesive 39 cured. After the adhesive 39 cures, the twosurfaces would be held in place by the adhesive 39 with longitudinalmechanical vibration and/or shock pulse motion transferring from theamplifying coupler sub-unit 2 into the material 3 through the adhesive.

As a final example, shown in FIG. 25, the attachment or joint betweenthe amplifying coupler sub-unit tip surface 20 and material edge 27could be made nonexistent by forming the amplifying coupler sub-unit 2and the material 3 from a single piece of material 3.

In any case, it is nonetheless advantageous to ensure a good attachmentexists between the amplifying coupler sub-unit tip surface 20, which isexperiencing longitudinal mechanical vibration and/or shock pulse motion19, and the material edge 27. In a preferred embodiment, the amplifyingcoupler tip sub-unit surface 20 and the material edge 27 substantiallyremain in compression or have a strong adhesive 39 joint between them.

An additional feature of the amplifying coupler sub-unit 2, as shown inFIG. 26, is that it can be designed to direct the longitudinalmechanical vibration and/or shock pulse motion developed by theconverter sub-unit 1 in a direction and/or plane of reference which isnot the same as the longitudinal mechanical vibration and/or shock pulsemotion in the material 3.

6.0 Amplifying Coupler Sub-Unit to Material Surface Material Matching

In addition to ensuring a good compressive or adhesive attachmentbetween the amplifying coupler sub-unit tip surface 20 and the materialedge 27, it is also advantageous to understand what impedance valuesexists between the materials used for the amplifying coupler sub-unit 2and the material 3. By understanding the material impedances, the valuesof the stress wave reflection and stress wave transmission coefficientscan be calculated at the interface of the amplifying coupler sub-unittip surface 20 to material edge 27. The longitudinal vibration motion 19of the amplifying coupler sub-unit tip surface 20 is transferred by aforce from the amplifying coupler sub-unit tip surface 20 pushing upagainst the material edge 27. Since this force is acting through thecross sectional area of the amplifying coupler sub-unit tip surface 20,a stress state is present at this interface. An efficient matchingprocess of the materials and area changes between the amplifying couplersub-unit 2 and material 3 are similar as was described in section 3.0.

7.0 Material with Debris Attached

The material 3 of interest has the debris 5 that is to be removed. Forexample, and as shown in FIG. 27, this material surface may serve thepurpose of the windshield of an automobile 40 which is caused to vibrate41 by the vibrating debris remover 6. It may also be the leading edge 42of an aircraft wing 43 as shown in FIG. 28, or any of a plurality ofother materials that may have debris attached. In any case, theexistence of debris 5, such as ice and water, on the material 3 surfaceis not desired and is to be removed.

8.0 Designing an Efficient Vibrating System

In order that sufficient relative acceleration, strain, and strain ratecan be achieved at the interface between the debris 5 and material 3, anefficient design must be developed. An efficient design for thevibrating debris remover 6 invention not only has to deal with theimpedance matching of the converter sub-unit 1 to the amplifying couplersub-unit 2 and the amplifying coupler sub-unit 2 to the material 3 ofinterest, but it also must be designed to vibrate with the least amountof energy 4 as possible while achieving the highest accelerations andstrain rates in the material 3 and debris 5. This condition is known asresonance. Once the resonance state is achieved, the particle motions inthe amplifying coupler sub-unit 2 and the material 3 of interest canhave much greater amplitudes than the motions present in the materialparticles of the converter sub-unit 1. If low material damping ispresent, high Q or amplification values can be achieved. The result ofhigh Q values is particle motion 36 and accelerations in the material 3of interest which will cause the adhesive bond with the debris 5particles to be broken.

To achieve resonance, the frequency of vibration of the convertersub-unit 1, amplifying coupler sub-unit 2, and the material 3 ofinterest must be the same (or within very close tolerance). Therefore,the operating frequency of the converter sub-unit 1 and the amplifyingcoupler sub-unit 2 must both be based on the frequency of a waveformtraveling in the material 3.

Referring to FIG. 20, the fundamental frequency of vibration of alongitudinal wave in the material 3 can be calculated from mathematicalequation (6).

$\begin{matrix}{f_{m} = \frac{v_{m}}{2L_{m}}} & {{Equation}\mspace{20mu}(6)}\end{matrix}$Where:f_(m)=fundamental frequency of longitudinal wave in the material 3(cycles/sec or Hz)v_(m)=longitudinal sound velocity in material 3L_(m)=length of the material 3

Once the vibration fundamental frequency of a longitudinal waveform inthe material 3 has been determined, it is advantageous to determine thephysical dimensions for the amplifying coupler sub-unit 2 such that italso wants to vibrate at the same frequency (f_(m)). In addition, theconverter sub-unit 1 may be designed to operate at this same frequency(f_(m)).

Since the amplifying coupler sub-unit 2 is preferably to be designed tovibrate at the same or similar frequency as the material 3, and astepped amplifying coupler sub-unit is easily manufactured, equation (7)has been derived to determine the required length (l_(c) as shown inFIG. 17) of a stepped amplifying coupler sub-unit in order for it tovibrate at the same frequency (f_(m)) as the material 3. For a steppedamplifying coupler sub-unit in which the length of the larger crosssectional area (a_(c) as shown in FIG. 17) is equal to one half of thetotal amplifying coupler sub-unit length (a_(c)=½l_(c) as shown in FIG.17) the following equation can be developed:

$\begin{matrix}{{{\frac{S_{a}}{S_{b}}{\sin( \frac{\pi\; l_{c}v_{m}}{2L_{m}v_{c}} )}{\cos( \frac{\pi\; l_{c}v_{m}}{2L_{m}v_{c}} )}} + {{\cos( \frac{\pi\; l_{c}v_{m}}{2L_{m}v_{c}} )}{\sin( \frac{\pi\; l_{c}v_{m}}{2L_{m}v_{c}} )}}} = 0} & {{Equation}\mspace{20mu}(7)}\end{matrix}$Where:v_(m)=speed of sound in the material 3L_(m)=length of material 3v_(c)=speed of sound in the amplifying coupler sub-unit 2 materiall_(c)=length of amplifying coupler sub-unit 2S_(a)=cross sectional area of amplifying coupler sub-unit 2 larger end17S_(b)=cross sectional area of amplifying coupler sub-unit 2 smaller end20

If proper impedance matching is performed between all materials and thevibrating debris remover 6 is designed to vibrate at the same frequency(f_(m)) as the material 3, then an energy efficient system will bedeveloped.

9.0 Designing an Efficient Shock Pulse System

In order that sufficient relative acceleration, strain, and strain ratecan be achieved at the interface between the debris 5 and material 3, anefficient design must be developed. The most efficient design for theshock pulse debris remover 6 invention not only has to deal with theimpedance matching of the converter sub-unit 1 to the amplifying couplersub-unit 2 and the amplifying coupler sub-unit 2 to the material 3 ofinterest, but the amplifying coupler sub-unit 2 should be designed tovibrate at a resonant frequency as the material of interest.

The frequency of vibration of the amplifying coupler sub-unit 2 and thematerial 3 of interest should be the same (or within close tolerance).The operating frequency of the amplifying coupler sub-unit 2 is based onthe frequency of a longitudinal waveform traveling in the material 3determined from equation 6. Once the vibration frequency of the waveformin the material 3 has been determined, it is advantageous to determinethe physical dimensions for the amplifying coupler sub-unit 2 such thatit also wants to vibrate at the same frequency. The process of designinga stepped amplifying coupler sub-unit for a vibrating system wasdescribed in Section 8.0 using equation (7). This exact same process isused to design a stepped amplifying coupler sub-unit for a shock pulseconverter sub-unit 1. In fact, the amplifying coupler sub-unit designedin Section 8.0 is the exact same stepped amplifying coupler sub-unitdesigned for a shock pulse converter sub-unit 1

For a vibrating debris remover 6 designed to produce a shock pulse ormultiple shock pulses, only the amplifying coupler sub-unit 2 has to bedesigned to vibrate at the same frequency as the material 3 for anenergy efficient system to be developed, as was similarly done for thevibrating system.

The principles, preferred embodiments and modes of operation of thepresent invention have been described in the forgoing application. Theinvention which is intended to be protected herein should not, however,be construed as limited to the particular forms disclosed, as these areto be regarded as illustrative rather than restrictive. Variations andchanges may be made by those skilled in the art without departing fromthe spirit of the present invention. Accordingly, the foregoing detaileddescription should be considered exemplary in nature and not limited tothe scope and spirit of the invention as set forth in the appendedclaims.

1. A device for removing debris from a material, comprising: a converterunit that produces mechanical motion at an output; an amplifying couplerhaving a first end and a second end, the first end being operablyassociated with the output so as to transmit the mechanical motionproduced by the converter unit, the second end being adapted to attachto a material, wherein, a cross-sectional area of the amplifying couplerat the first end is greater than a cross-sectional area of theamplifying coupler at the second end.
 2. The device as recited in claim1, wherein the change in cross-sectional area between the first end ofthe amplifying coupler and the second end of the amplifying coupler isstepped.
 3. The device as recited in claim 1, wherein the change incross-sectional area between the first end of the amplifying coupler andthe second end of the amplifying coupler is linear.
 4. The device asrecited in claim 1, wherein the change in cross-sectional area betweenthe first end of the amplifying coupler and the second end of theamplifying coupler is curved.
 5. The device as recited in claim 1,wherein the converter unit transforms energy selected from the groupconsisting of: electrical, pneumatic, and fluid energy.
 6. The device asrecited in claim 1, wherein the coupler is attached to the material, andthe converter, amplifying coupler, and material each have an impedance,the impedance of the converter being substantially equal to theimpedance of the amplifying coupler.
 7. The device as recited in claim6, wherein the impedance of the amplifying coupler is substantiallyequal to the impedance of the material.
 8. The device as recited inclaim 1, wherein the coupler is attached to the material, and theconverter, amplifying coupler, and material each have an impedance, andwherein the impedance of the amplifying coupler is substantially equalto the impedance of the material.
 9. The device as recited in claim 1,wherein the converter unit includes a shaft having a longitudinal axis,the converter unit being adapted to reciprocate the shaft axially. 10.The device as recited in claim 1, wherein the amplifying coupler iscompressively attached to the material.
 11. The device as recited inclaim 1, wherein the amplifying coupler is mechanically attached to thematerial.
 12. The device as recited in claim 1, wherein the amplifyingcoupler is adhesively attached to the material.
 13. The device asrecited in claim 1, wherein the amplifying coupler is removably attachedto the material.
 14. The device as recited in claim 1, wherein thematerial is glass, and the device is attached to the glass.
 15. Thedevice as recited in claim 1, wherein the material is a windshield, andthe device is attached to the windshield.
 16. The device as recited inclaim 1, wherein the mechanical motion is vibratory motion.
 17. Thedevice as recited in claim 1, wherein the mechanical motion is a shockpulse.
 18. The device as recited in claim 1, wherein the material, theamplifying coupler, and the converter each have at least one resonantfrequency, the resonant frequency of the material being substantiallyequal to at least one of the resonant frequencies of the amplifyingcoupler and the converter.
 19. The device as recited in claim 18,wherein the resonant frequencies of the material, amplifying coupler,and converter are all substantially equal.
 20. The device as recited inclaim 18, wherein the material has a major dimension, and a minordimension defining an edge, the amplifying coupler being attached to theedge.
 21. The device as recited in claim 1, wherein the material has amajor dimension, and a minor dimension defining an edge, the amplifyingcoupler being attached to the edge.
 22. The device as recited in claim1, wherein the amplifying coupler is attached to the output of theconverter by a threaded stud.
 23. The device as recited in claim 1,wherein the amplifying coupler is monolithic with the output of theconverter.
 24. A device for removing debris from a material, thematerial having a plurality of resonant frequencies, including afundamental resonant frequency and multiples of the fundamental resonantfrequency the fundamental resonant frequency being determined bydividing the velocity of sound through the material by two times thelength of the material, the device comprising: a converter unit thatproduces mechanical motion at an output; and, a coupler unit attached toboth the converter unit output and the material, the coupler unit havinga resonant frequency and being operable for transmitting the mechanicalmotion produced by the converter unit into the material; wherein, one ofthe resonant frequencies of the material is substantially equal to theresonant frequency of the coupler.
 25. The device as recited in claim24, wherein a resonant frequency of the converter unit is substantiallyequal to the resonant frequency of the coupler.
 26. A device forremoving debris from a material, the material having a major dimension,and a minor dimension defining an edge, the device comprising: aconverter unit that produces mechanical motion at an output end thereof;and, a coupler unit having a first portion attached to the output end ofthe converter unit, and a second portion attached to the edge of thematerial.
 27. The device as recited in claim 26, wherein the couplerunit conducts mechanical motion into the material at an anglesubstantially perpendicular to the edge of the material.
 28. The deviceas recited in claim 26, wherein the coupler unit has a longitudinalaxis, the coupler unit being operable to translate axially in responseto the mechanical motion produced at the output end of the converterunit, the longitudinal axis of the coupler unit being substantiallyperpendicular to the edge of the material.
 29. A device for removingdebris from a material, comprising: a converter unit that producesmechanical motion at an output; a coupler having a first end and asecond end, the first end being operably associated with the converteroutput so as to transmit the mechanical motion produced by the converterunit, the second end being attached to the material; wherein, theconverter unit, coupler, and material each have an impedance, theimpedance of the coupler being substantially equal to the impedance ofthe material.
 30. The device as recited in claim 29, wherein theimpedance of the coupler is substantially equal to the impedance of theoutput of the converter.